1. Technical Field
The present invention relates to a construction machine including a heat exchanger and an air suction structure for introducing outside cooling air and guiding the air to the heat exchanger.
2. Description of the Background Art
The background art of the present invention will be described taking an excavator shown in FIG. 4 to FIG. 6 as an example.
The excavator includes a crawler-type lower travelling body 1, an upper slewing body 2 mounted on the lower travelling body 1 so as to be able to slew around an axis O perpendicular to the ground, and a front attachment 3 for an excavation operation attached to a front portion of the upper slewing body 2; the lower travelling body 1, the upper slewing body 2, and the front attachment 3 are shown in FIG. 4 and FIG. 5. In the specification, “front-back” and “lateral” mean directions as viewed from inside a cabin 4 installed in the upper slewing body 2.
The excavator further includes a rear guard panel 5 that covers an engine room 6 positioned in a rear portion of the upper slewing body 2, a counterweight 11, and a side guard panel 12, as also shown in FIG. 6.
The engine room 6 forms a first device accommodation space that accommodates devices. The devices include an engine 7, a hydraulic pump 8, a cooling fan 9 and a heat exchanger 10, which are laterally juxtaposed so as to locate the heat exchanger 10 at the right end of the lateral arrangement. The heat exchanger 10 includes a radiator and an oil cooler. The cooling fan 9 rotates to introduce outside cooling air and blow the air through the heat exchanger 10. The rear guard panel 5 has a non-graphically-shown top panel that is openable and closable, for example, like a hood for maintenance of the engine 7 or the like. The counterweight 11 is installed in an area behind the engine room 6, that is, at a rear end of the upper slewing body 2.
The side guard panel 12 covers a device room 13 positioned on a right side of the upper slewing body 2 (opposite to the cabin 4). The device room 13 forms a second device accommodation space that accommodates devices, extending in a front-back direction to communicate with the engine room 6 at a rear portion of the device room 13. The devices accommodated in the device room 13 include tanks, valves, and a battery.
The side guard panel 12 has a first panel 14 and a second panel 15. The first panel 14 is an immobile, fixed panel and has an opening 14a for maintenance located at an upper end of the first panel 14 and shown in FIG. 4 and FIG. 5. The second panel 15 is connected to the first panel 14, similarly to the top panel of the rear guard panel 5, so as to open and close the opening 14a like a hood. Specifically, the second panel 15 has a left peripheral portion, that is, a cabin 4-side peripheral portion, which is connected to an opening edge of the first panel 14 through a hinge. The second panel 15 pivots around the hinge to open and close the opening 14a. 
The second panel 15 is attached with a seal member (not shown in the drawings), for example, a weather strip, in a peripheral portion of the second panel 15. The peripheral portion of the second panel 15 can be supported by the opening edge of the first panel 14 in a state where the second panel 15 is closed, and, upon this, the seal member makes close contact with the opening edge.
This type of excavator preferably has an air suction structure for feeding outside cooling air toward the heat exchanger 10. As such an air suction structure, a commonly known is one disclosed in Japanese Patent Publication Laid-open Nos. 2010-30472 and 2007-39936, that is, a structure having a guard panel that covers a device accommodation space (in the excavator described above, the engine room 6 or the device room 13), the guard panel including a plurality of openings, namely, air suction ports. By way of example, FIG. 4 to FIG. 6 show air suction ports 16 formed in a front right side surface portion of the second panel 15 constituting the side guard panel 12. Each of the air suction ports 16 is shaped like a slot that is elongate in the front-back direction. Moreover, there can be a case of providing an air suction port also in the first panel 14 or the rear guard panel 5.
Furthermore, in recent years, the required amount of introduced outside air has tended to increase in conjunction with larger power facilities resulting from emission control and the like, which involves a requirement of the sum of the areas of air suction ports, that is, in the total opening area, specifically, a requirement of an increase in the number and size of air suction ports. However, such an increase in the number and size of air suction ports may degrade the appearance of the excavator or accelerate external leakage of noise such as engine sound and infiltration of rainwater. Moreover, a decrease in the effective area of the guard panel may make application of design decals and a caution label be difficult. As means for waterproof measures against an increase in the number of the air suction ports, there can be application of a louver to the air suction ports or improvement of a process of making electric components waterproof; however, these measures involve a significant increase in costs.